Holder for an electric lamp



April 1, 1969 c. w. HEATH 3,436,717

HOLDER FOR AN ELECTRIC LAMP Filed Feb. 6, 1967 INVENTOR C1 HRENCE NHL/9N6 Iii/777i;

ATTORNEY April 1, 1969 c. w. HEATH 3,435,717

HOLDER FOR AN ELECTRIC LAMP Filed Feb. 6; 1967 Sheet 5 of 2 INVENTOR PM a. PM,

ATTORNEY United States Patent C 3,436,717 HOLDER FOR AN ELECTRIC LAMP Clarence Willans Heath, Bleasby, England, assignor to United-Carr Incorporated, Boston, Mass, a corporation of Delaware Filed Feb. 6, 1967, Ser. No. 614,349 Claims priority, application Great Britain, Feb. 9, 1966, 5,677 66 Int. Cl. H01r 13/20, 13/62 US. Cl. 339-65 2 Claims ABSTRACT OF THE DISCLOSURE A lampholder has the inner surface of the lamp receiving cavity shaped to define inwardly sloping surfaces for orienting the lamp as it is inserted and guiding it into correct register with the cavity.

This invention relates to a holder for an electric lamp, more particularly a holder for a capless type lamp of the kind having an oblong-shaped base adapted to make a sliding fit in the holder, contacts being provided on the outer side walls of the base for engaging contacts in the holder.

Such lampholders are often of relatively small size and mounted on supports such as parts of a motor vehicle which are not easily accessible for the insertion of the lamp. As the dimensions of the lamp base correspond fairly closely to that of the lamp receiving cavity in the holder, it is necessary that the base be accurately aligned with the cavity when the lamp is being inserted, and where access to the holder is restricted there is very little room for an operator to manipulate the lamp base and the alignment of the lamp base and cavity in the socket is usually a matter of trial and error which necessarily slows up the assembly and results in a considerable loss of time where a considerable number of lamps have to be assembled in the holders.

It is an object of the invention to provide a holder with means for facilitating the above mentioned alignment thereby enabling the lamp to be easily and quickly inserted.

The present invention provides a holder for an electrical lamp having a base of oblong shape in cross-section, the holder comprising a body of electrically insulating ma terial having a cavity of oblong shape in cross-section for receiving the base of the lamp, the inner wall of the cavity adjacent the lamp receiving end thereof being shaped to provide smoothly curved inwardly sloping surfaces for effecting the rotation of the lamp base, on being inserted into the lampholder, so as to correctly align the major and minor axes of the lamp base with the respective major and minor axes of the oblong-shaped cavity.

Two opposed cam-shaped surfaces may be provided so disposed as to be engageable by the end portions of the lamp base and so disposed that irrespective of the position of the lamp base relative to the cavity in the holder, the base will be guided over the surfaces and rotated into correct alignment. No manipulative skill is required by the person inserting the lamp as all that is necessary is to present the end of the lamp base to the mouth of the cavity so as to engage the cam surfaces, normal force exerted in inserting the lamp being sufficient to cause the base to slide over the cam surfaces so as to be guided automatically into the cavity.

To enable the invention to be fully understood, it will now be described, by Way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a perspective view of a lampholder for a capless type lamp according to one embodiment of the invention;

FIGURE 2 is a plan view thereof;

FIGURE 3 is a sectional side view on the line AA of FIGURE 2;

FIGURE 4 is a sectional side view on the line B-B of FIGURE 2; and

FIGURE 5a, 5b and 5c are fragmentary sectional views on the lines XX, YY and ZZ, respectively of FIGURE 2.

As illustrated in the drawings, the lampholder comprises a body 1 formed of electrically insulating material such as synthetic plastics having an axial cavity 2 for receiving the base of a lamp. The particular holder illustrated in the drawings is adapted for receiving the base of a capless lamp of the kind referred to, and accordingly the cavity is of oblong shape in cross-section corresponding to that of the base of the lamp. Contacts (not shown) will normally be assembled in the cavity adjacent opposed side walls for engagement with contacts provided on the outer surface of the opposed walls of the lamp base which is adapted to make a sliding fit in the cavity.

At the mouth or open end of the cavity the body is shaped to provide inwardly sloping cam-shaped surfaces 3 on each of the longer sides of the oblong-shaped cavity, the surfaces being mirror images of one another and providing smoothly curved portions progressing from a steeply sloping portion at one end (see FIGURE 5a) and intermediately sloping portion (see FIGURE 5b) and a shallow sloping portion (see FIGURE 50). The lower end of the latter portion terminates at the edge of the lamp receiving cavity at one end thereof.

Accordingly, when the end of the lamp base is presented to the cavity, it will engage the opposed inwardly sloping cam surfaces and the normal applied pressure for inserting the lamp will cause the base to slide over the surfaces which will automatically effect the rotation of the base so that on reaching the end of the cam-shaped portion illustrated in FIGURE 50, the base will have been oriented so as to align the major and minor axes of the lamp base with the major and minor axes of the cavity to bring the lamp base in correct alignment with the cavity into which it will be automatically guided. It will be understood that the initial angular relation of the lamp base to the cavity is immaterial as whatever portion of the cam surfaces are engaged initially, the base will be automatically oriented into correct alignment.

As the opposed inwardly sloping cam surfaces are mirror images, each will be engaged by an end portion of the lamp base and rotated and guided into alignment with the cavity.

As illustrated in the drawings, the body 1 is formed with a central axially extending wall 4 leading from the inner end of the cavity 2 to the outer end of the body 1. Tail portions of the contacts which are adapted to be as sembled in the holder will normally extend through the passages 5, 6, on the opposite sides of the wall 4 so that the latter will serve to insulate the contacts from one another.

The holder is provided with an annular outwardly extending radial flange 7 at the lamp receiving end and with lateral projections 8 adjacent the underside of the flange. The holder is adapted to be assembled in an aperture in a support by inserting the body 1 through the aperture until the flange 7 abuts one face thereof. A fastener device such as a ratchet plate having an aperture defined by the free ends of resilient tongues is adapted to be forced over the lateral projections 8 so that the tongues frictionally grip the outer surfaces of the projections and the ratchet plate abuts the opposite face of the support to secure the holder in assembly.

I claim:

1. A holder for an electrical lamp having a base of oblong shape in cross-section defined by major and minor axes, the holder comprising a body of electrically insulating material, a cavity of Oblong shape in cross-section defined by major and minor axes, formed in said body for receiving the base of the lamp, smoothly curved inwardly sloping surfaces in the form of a helix provided in said cavity for effecting the rotation of the lamp base, on being inserted into the said cavity, so as to correctly align said major and minor axes of the lamp base with the respective major and minor axes of the oblong-shaped cavity.

2. A lampholder as claimed in claim 1, wherein the said body comprises an oblong-shaped portion having an outwardly extending radial flange at the lamp receiving end and portions adjacent the underside of the flange extending laterally of the oblong-shaped body portion and ter- References Cited UNITED STATES PATENTS 913,024 2/1909 Meacham 339-128 2,354,748 8/ 1944 Franklin 339129 2,576,363 11/1951 Rively et a1.

3,118,717 1/1964 Horan 3392l9 3,324,442 6/ 1967 Greasley.

MARVIN A. CHAMPION, Primary Examiner.

J. H. MCGLYNN, Assistant Examiner.

US. Cl. X.R.

minating in inwardly spaced relation to the peripheral 15 339l29 edge of the flange. 

